This still seems firmly based on the idea that it is possible to plan a project completely from the outset correctly. I don't think that is possible, you only see all the problems when you try to do something and incremental progress has a lot less inaccuracy all be it with very poor future prediction. We put far too much emphasis on projects up front when we understand the least. Such budgets and project plans are useful for choosing between projects maybe but they don't stand contact with the problem.
This advice really misses the fundamental reason why projects fail and advocates for more of the things that are impossible and cause the failures!